ScrollTo can not run well in iOS

I use $$('.page-content').scrollTo(0, 0, 1000) to scroll the page to top, but sometime it doesn’t run well,
and when I set the css to page-content like:

  1. $$('.page-content').css('overflow', 'hidden')
  2. $$('.page-content').css('overflow', 'auto')

the scrollTo function can be run, but the screen will blank for a few milliseconds when I change the ‘overflow’ css,
I don’t know why this problem is only show on iOS, and the website is no problem.